Question: Simplify the following expression: $k = \dfrac{9n}{5} + \dfrac{n}{2}$
Solution: In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $5$ and $2$ $\lcm(5, 2) = 10$ $ k = \dfrac{2}{2} \cdot \dfrac{9n}{5} + \dfrac{5}{5} \cdot \dfrac{n}{2} $ $k = \dfrac{18n}{10} + \dfrac{5n}{10}$ $k = \dfrac{18n +5n}{10}$ $k = \dfrac{23n}{10}$